I'm on a 12th gen intel processor and see RAM overload, except my game refuses to allocate outside the instance and caps itself at the 8gb I have it set to. Causes major lag spikes after so many days playing because loading anything ends up using the entire allocation instantly before purge repeatedly in certain scenarios.
3070, 12700k intel processor, 32gb RAM. Allocating above 8gb I have seen cause unavoidable purge lag spikes, but allocating about 10gb is where DH behaves best, I've read.
I've used DH on a couple different modpacks now with very different sets of mods, and even in vanilla instances it refuses to use RAM outside allocation like it's suppsed to (?). I can't see a good balance point for this. Setting it to lowest CPU usage and pregenning for days helps for immediate chunk visibility, but just existing in preloaded chunks has become laggy. These are chunks that have been loaded for hundreds of days with a very wide perimeter, so I can't see why RAM would spike like that. This is especially noticeable when traveling in the Nether or Aether, even at low speeds like when mining tunnels, which is maybe 0.2m/s speed. No more or less noticeable when riding a fast horse down said tunnels, or flying a moa over long distance in Aether.
On a much heavier modpack, it's nearly impossible to avoid having to restart the game every 30min-1hr just existing after preloading over 20k in each direction. The game not only requires a bit more RAM than usual, something like 3gb standing, it eats it up WAY faster with DH working. I never have distant generation on in this instance. The game behaves like it has a memory leak, but I have yet to find any plausible culprit other than DH. This would be on DH v2.1.2 and a couple versions below for all of this. I thought this issue was limited to having too much land cached as LODs, which kind of helped, but just existing seems to cause degradation of performance.